The benefits of chillers include flexibility in installation spaces and water piping layouts. The chiller cools water being circulated to cooling coils that in turn transfers heat and latent heat from the air to the chilled water. The selection of how many components are used and how they are laid out is relatively flexible; thus, this system meets various requirements for high air conditioning capacity and larger spaces, which in turn widens commercial and industrial applications. For a chiller system, you don't have to take account of constraints in direct expansion air conditioning, e.g., height differences and length of refrigerant piping.
It effectively uses waste heat, steam, and/or hot water produced in the manufacturing processes. Cogeneration systems that leverage waste heat (from hot water) are the common applications that benefit from chiller cycles.
An air handling unit (AHU) is the key component of an air conditioning system. It takes in outdoor or ventilated air, removes particles and dust, controls temperature and humidity levels, and supplies conditioned air via ducts.
Inside an AHU casing are water cooling/heating coils, reheating coils, a humidifier, an air filter, and blower. An AHU is typically installed in a machine room specifically designed for it. With all the components modularized and packaged in a single unit, most AHUs provide ease of maintenance. Typically, the heat source of an AHU is a chiller or VRF that exchanges heat between chilled/heated water or refrigerant and ambient air for creating conditioned air. Combining a chiller and AHU can build an air conditioning system suited for mid-to large-sized buildings, while VRF and AHU used together to provide a system that works best for small-to mid-sized buildings.
In a central air conditioning system, a heat source device installed in the building heats the water circulating in the system. The water flows to and from an AHU to provide conditioned air. By contrast, individual air conditioning systems have heat sources for each floor and area.
A central air conditioning system employs heat source equipment, e.g., refrigerator, boilers, fitted with an evaporator fan coil of an air handling unit or fan coil. The term comes from the fact that all heat source components are accommodated in a single housing, from which conditioned air is delivered via a warm/cold air supply duct.
Often, central air conditioning systems are the choice for large buildings and facilities.
There are many advantages to a central unit system that can make it a worthwhile investment. You have a choice from among hundreds of different models of central air systems. Freely locatable chiller/AHU, piping layout, and fewer constraints in ductwork and piping lengths, allow for building design flexibility. During a cooling cycle, for example, the water cooled in the chiller travels to the condenser coil that expels heat into the atmosphere, then the fan delivers cooled air into the duct. These components can be flexibly combined and laid out to meet the requirements of your air conditioning scene regardless of the capacity required or the volume of the space to be cooled. Another benefit is that you don't have to take into account the constraints that usually come with direct expansion air conditioning, e.g., height differences of components, length of refrigerant piping, limits in air volume or static pressure.